CUERPOS ALCALINOS BASICOS PALEOGENOS DEL SUR DE SOMUN CURA (ARGENTINA) Y SU MARC0 ESTRATIGRAFJCO

A. A. ARDOLINO; BUSTEROS, A.; CUCCHI, R.; FRANCHI, M.; LEMA, H.; REMESAL, M.B,

PUBLICACION ESPECIAL - ASOCIACION PALEONTOLOGICA ARGENTINA

ASOCIACIÓN PALEONTOLÓGICA ARGENTINA

Lugar: Buenos Aires; Año: 1995 vol. PE3 p. 7 - 22

0328-347X

PAL EOGENE ALKALINE BASIC INTRUSIVES FROM SOUTHERN SOMUN CURA (ARGENTINA). Stratigraphic SEtTiNG. Eocene alkaline-basic intrusives crop out at the southern border of Somun Cura Plateau, near Bajada del Diablo and Gan Gan. These intrusive bodies are included in The Buitre Formation. It shows doniic or tabular sapklol)w~i th diameien nnging from I to 3 km. El Buitre Fomiation shows intrusion relation with the Senoniatl sedinients dhC Xmia Fonnuion. kis Ihe retations with other formations, such as Snnniento tuff or Son~dnC ura bnsnlta are unknown. Ik h m s k s fras &jda dcl DiaMo lad Gm Gan show lithologic and niorphologic siriiilitudes with Eocene iritmsives of aLer H i e r ncb u El Sombrero, Wonia SInnienlo and lngeniero Jacobacci. Tlierefore. the intmsiver could constitute n 350 tn bag141 discnettiamoms kh in Cbobnt Province, Argentina. The petrographic cliarncteristics of tliese iritruzive bodies rbr th Lbty fam a ybbm - foid gabbro - foid mmwgahbro serie with rare syer~iticc oni~msitions.I ts grain size varies fro111 vay cearse & I fm:s ~ e l r rm. yric a d s ubophitic textures are prevailing. Typicnl milleralogic association is plapioclnse (An 48-562) - climpymmc - oliviec - o~wlucm imnlr and analcinie. Minor coniponents are alkali feldspar. reldsl~nllioids. biotite .ad .price. El Buitrc Fomion un be a n s i d e d as a subvolcanic event of a subsrturnted sodic alkalirie niagriintisrn Ih cbrrrdrrilt, ecmtincutal iotnplale ~ g i m s